Most buildings that have eaves have water collecting troughs underneath to collect the rain flowing down from the eaves and guide the rain to the drainpipe or to discharge on the ground. The water collecting trough has to be cleaned frequently to avoid clogging by sand, leaves, branches, etc carried by rain. Thus, some people developed a water spraying device to clean the water collecting trough as shown in FIGS. 10 and 11. The water spraying device has a water inlet unit (40) that has a water inlet end (41) underneath to connect to a water supply. A water control valve (42) is located near the water inlet end (41) to control the amount of water input, and a water guiding channel (43) that is bended forward is disposed on an upper portion of the water inlet unit (40), the water guiding channel (43) connecting to a flat water outlet head (44) at the rear end. When in use, the water spraying device is moved upward so the water outlet head (44) can be aligned with the water collecting trough. Meanwhile, the water control valve (42) is turned on, so water can flow from the water inlet unit (40) and the water guiding channel (43) to the flat water outlet head (44) to form a strong water column to clean the water collecting trough. However, the angle of the water guiding channel (43) is fixed, and the water spraying direction of the water outlet head (44) is fixed as well, so when the user wants to clean the water collecting trough, the user has to move the water inlet unit (40) to indirectly adjust the angle of washing, since the water inlet unit must be moved frequently and water may randomly spray and splash the user.
Therefore, there remains a need for a new and improved washing device having an adjustable water outlet head to achieve the goal of convenience and easy operation to overcome the problems stated above.